Process of extracting metals from their ores.



UNITED STATES PATENT OFFICE.

HENRY 1B. SLATER, or RIVERSIDE, CALIFORNIA, ASSIGNOR or ONE-HALF '10 RANSOM B. SHELDEN, or RIVERSIDE, CALIFORNIA.

PROCESS OF EXTRACTIN G METALS FROM THEIR ORES.

No Drawing.

To all whom, it may concern:

Be it known that I, HENRY B. SLATER, a citizen of the United States, residing at Riverside, in the county of Riverside and State of California, have invented new and useful Improvements in Processes of Extracting Metals from Their Ores, of which the following is a specification.

This invention relates to improvements 1n processes for the extraction of metals from their ores, and has particular relation to the production of a sol-vent or oxidizing lixiviant for oxidizing and dissolving the metallic contents of various ores.

The process of the present invention is especially well adapted for oxidizing and dissolving the metals of sulfid ores of copper and other metals without the intervention of a calcining or roasting process, and with an attendant recovery of the sulfur as a by-product.

It is an object of the invention to provide such' a lixiviant so that it shall contain 0xi dizing compounds capable of producing the oxidation of the ore and the liberation of the sulfur.

It is a further object of the invention to produce a lixiviant by electrolytic means, and enriching the anode solution employed with ferric chlorid by the addition of ferric hydroxid.

It is also an object of the invention to formsuch a lixiviant and further enrich the anode solution with oxidizing compounds of a still more active and unstable character by the formation of hypochlorite of sodium, hypochlorous acid, chloric acid and chlorin peroxid.

The preferable method of carrying out the process will now be described, and since the invention lies in the provision of a peculiar kind of solvent and the method of the preparation thereof, the description of said solvent and the process of producing same will now be taken up. Taking certain proportions of the materials used as an example, the process may be described as follows: In the formation of the lixiviant,

about a 15% solution of sodium chlorid in water is taken, to which is added 1% of iron, preferablyin the form of ferrous chlorid. This mixed solution is then placed in a two-part electrolytic cell having a cathode compartment and an anode compartment,

separated by a porous, noncondu'cing par-- Specification of Letters Patent.

Patented July 8, 1913.

Application filed March 13, 1912. Serial No. 683,646.

tition or diaphragm. The anode is prefer ably composed of graphite, While the oathode 1s usually a sheet of copper. The solution just described is the same in both compartments of the cell. Upon passing a current of electricity through the cell from the carbon or graphite anode to the copper cathode, chlorin is liberated at the anode, and combining with the ferrous chlorid present in the solution, raises it to ferric chlorid. At the same time, sodium is given up at the cathode and decomposes the water, with a consequent formation of sodium hydroxid, and the liberation of hydrogen. The sodium hydroxid precipitates the iron of the ferrous chlorid as ferrous-ferric hydroxid. When all of the iron in the anode compartment has been raised to the ferric state, I add to the anode solution a part of the cathode products from the cathode compartment, consisting of sodium hydroxid and ferrous-ferric hydroxid. The sodium hydroXid meeting the chlorin which is being generated at the anode will combine therewith to form sodium hypochlorite and sodium chlorid as per the following reaction:

Water,v will form hypochlorous acid in ac cordance with the following reaction:

(2.) Cl,O+H O:2HClO.

Care should be taken that at no time the caustic soda from the cathode compartment be added to the anode compartment in a quantity suflicient to take part in the electrolysis, its office being solely that of an agent to react with the chlorin, which is being generated at the anode and not that of an electrolyte to be acted upon by the electric current.

After the iron which has been added to the anode compartment is also raised to the ferric state, the continued passage of the current will further enrich the anode solution in higher and more'active forms of oxidizing compounds. The chlorin, upon decomposing the water, will combine with the oxygen and hydrogen to form chloric acid and chlorin peroxid, which will be recognized at once by its disagreeable odor and the greenish yellow foam upon the surface of the solution. When this condition is reached, the solution is ready to be added to the ore for extracting its metal values.

Having thus prepared the lixiviant or solvent, attention is now turned to the manner of treating the ore therewith. The ore, having first been round to a fineness of twenty meshes to the inch or more, is then treated by adding the solution above described as a lixiviant to the ore, preferably in theproportion of two parts of solution to one part of ore, and agitating the pulp thus formed. With the proportions described, it will be found that such agitation of the pulp will bring to the surface the liberated sulfur, which may be removed in the form of a scum or foam. It will be found that the reaction is very rapid, and the more so, the finer the comminution of the ore.

lVhen thus treating copper ores, the copper will be found in solution as cuprous chlorid in sodium chlorid with ferrous chlorid. The hypochlorous acid, the chloric acid and chlorin peroxid have accomplished the oxidizing of the ore, thereby liberating the sulfur, and the oxid of copper will be found to have been dissolved by the ferric chlorid, reducing the latter to ferrous chlorid. Any silver present will have been converted to chlorid of silver, and part of it will be found in the solution of sodium chlorid. Gold, if present, will have been dissolved by the chlorin but reprecipitated by the ferrous salt, but is in such condition that another treatment with some of the original solution of the lixiviant will bring away all the remaining silver and gold also.

Copper can be recovered from the solution in several ways, of which there may be mentioned,

1st.-The passing of the solution over iron, which will precipitate the copper, together with the silver and gold, the copper being replaced in the solution by the iron, and the resulting solution will contain the original sodium chlorid and ferrous chlorid ofthe lixiviant, plus the ferrous chlorid formed by the displacement of the copper by the iron and very little else, since the chlorid solution does not become charged wit-h basic salts as would be the case if a suitable solution were employed. The materials thus remaining are ready for regeneration in accordance with the method above set forth for the original formation of the lixiviant and for another cycle of operations.

2nd.The copper obtained from the ore after treating it with the lixiviant as above described, can be precipitated by electrolysis in a two'part cell, using an insoluble anode, a part of the copper being deposited upon the cathode and the remainder of the copper in the solution being raised to the cupric state, while the iron present will also be raised to the ferric state. This solution can now be used to extract the remainder of the copper from the ore, if any be left therein, and the remainder of the silver and all of the gold.

It will be observed from the above description that the addition of cathode products to the anode solution in the format-ion of the solvent or lixiviant is productive of important results and particularly of the formation of oxidizing compounds in the lixiviant which are capable of producing the oxidation of the ore and the liberation of the sulfur. Heretofore these results have necessitated the roasting or smelting of sulfid ores. The addition of cathode products to the anode solution also accomplishes the enrichment of the anode solution with ferric chlorid by the addition of the ferric hydroxid, and still further the enrichment of the anode solution with oxidizing com pounds of a still more active and unstable character by the formation of hypochlorite of sodium, hypochlorous acid, chloric acid and chlorin peroxid. The efliciency of the method is apparent in practice from the greater activity and effectiveness brought about in the formation of the lixiviant by the simple addition of cathode productsto the anode solution under the conditions above stated.

What is claimed is:

1. A lixiviant comprising the anode solution of electrolytically treated chlorids associated with halogen salts, said anode solution being mixed with hydroxids taken from the cathode solution, whereby the lixiviant is enriched with hypochlorite of sodium, hypochlorous acid, chloric acid and chlorin peroxid, constituting oxidizing agents and chlorin liberating means.

2. The process of preparing a lixiviant for the treatment of ores which consists in electrolytically treating a solution containing metallic chlorids and halogen salts and using the anode solution as a solvent, products of the cathode solution being added thereto for forming oxidizing compounds in the lixiviant, the said oxidizing compounds accomplishing the oxidation of the ore and the liberation of any sulfur present therein.

3. The process of preparing a lixiviant for the treatment of ores which consists in electrolytically treating a solution containing metallic chlorids, the anode solution employed being enriched with ferric chlorid by the addition of ferric hydroxid taken from the cathode solution.

4. The process of preparing a lixiviant for the treatment of ores, which consists in electrolytically treating a solution containing metallic chlorids, and adding portions Correction in Letters Patent No. 1,066,855.

5 dium, hypochlorous acid, chloric acid and chlorin peroxid.

5. A lixiviantcontaining the anode solution of an electrolytically treated solution of sodium chlorid and ferrous chlorid, said anode solution having sodium hydroxid and ferrous hydroxid obtained from the cathode solution mixed therewith, whereby the lixiviant is furnished with sodium hypochlorite, sodium chlorate, ferric chlorid, ferric oxychlorid, the said lixiviant also having therein hypochlorous acid, chloric acid and chlorin peroxid, due to continued electrolytic treatment.

6. The process of preparing a lixiviant for the treatment of ores which consists in electrolytically treating a solution cont-ain- 1913, upon the application of Henry improvement in of the case in the Patent Office.

[SEAL] Processes of Extracting Metals appears in the printed specification requiring correction as follows:

55, for the word suitable read sulfate,

Signed and sealed this 19th day of August, A.

ing sodium chlorid mixed With ferrous chlorid, the said latter chlorid being raised to the condition of ferric chlorid by the generation of chlorin under the action of electrolysis, and then adding to the anode solution, sodium hydroxid and ferrous hydroxid taken from the cathode solution, whereby the anode solution Will be furnished With sodium hypochlorite, sodium chlorate, ferric chlorid, ferric oxychlorid, the continued electrolytic treatment also forming hypochlorous acid, chloric acid and chlorin peroxid, in the lixiviant.

In Witness that I have hereunto subscribed by name this 5th day of March, 1912.

. HENRY B. SLATER.

\Vit nesses GASSELL SEvEnANon, EARLE R. PoLLARD.

It is hereby certified that in Letters Patent No. 1,066,855, granted July 8,

B. Slater, of Riverside, California, for an from their Ores," an error Page 2, line and that the said Letters Patent should be read with this correction therein that the samemay conform to the record THOMAS EWING,

Commissioner of Patents.

claim the foregoing I 

